144 hr free transit confirmation

Hi,
From what i understand, the 144 hour begins from 00:00 (midnight) following the date of your arrival into China, correct? Therefore you may have a little longer than 6 days if timing works out. For example, i fly into Shanghai on 1 november at 13:00, the visa however will not be activated until 00:00 on 2 November, effectively giving me until November 7th to travel around and then to fly out from Hangzhou.

Just looking for some confirmation regarding the above to put my mind at rest.
Korra